Apparatus and method for processing a semiconductor wafer

ABSTRACT

An apparatus and method for growing semiconductor quality oxide thermal layers on semiconductor wafers fast enough to be economically feasible as a single wafer process system. Process speed is insured by high pressure and high temperature. For example, if the pressure is about 100 atmospheres (1,500 psi) and at a temperature of 900° C., approximately 2.66 minutes are required to grow a 5,000Å oxide layer in a steam environment. The system can reach these operating conditions from ambient in approximately 30 seconds and depressurization and cool down require approximately 60 to 90 seconds. The apparatus includes a processing chamber to be pressurized with an oxidant, such as high pressure steam. The process chamber is contained in a pressure vessel adapted to be pressurized with an inert gas, such as nitrogen, to a high pressure. A pressure equalizing scheme is used to keep the fluid pressure of the process chamber and the pressure of the fluid pressure vessel substantially the same. The pressure equalization permits the use of thin walls for defining the process chamber.

This invention relates to improvements in processing of semiconductorwafers, more particularly, to an apparatus and method for processingsingle semiconductor wafers at a relatively high rate.

BACKGROUND OF THE INVENTION

The use of steam to grow oxides on semiconductor wafers is well knownand has been used extensively in the past. Typical temperatures of thesteam are about 900° to 1,000° C. and pressures are about 10 to 25atmospheres. At these operating conditions, a single wafer in a batch ofwafers can be processed but at a relatively slow rate, such as 2 hoursor more. It is often desirable to have a high throughput while providingfor acceptable process conditions.

Due to industry trends, processing of wafers is being done in smallerbatches and ultimately, processing will be done with single wafers. Thereasons for this single wafer trend include greater control of thewafer, the high cost of the wafers, and the size of the wafers. It ismuch easier to control a single wafer during processing than it is tocontrol a batch of wafers. Moreover, the cost of a wafer is relativelyhigh and with greater wafer control, the possibility of wafer damage orbreakage is minimized. Furthermore, the size of wafers is increasing.Typically, 6" wafers are now being used and it foreseeable that 8" and10" wafers will be used in the future. Because of the foregoingproblems, a need exists for improvements in the processing ofsemiconductor wafers as described above so that the processing can beeconomically feasible as a single wafer process system. The presentinvention satisfies this need.

Disclosures relating to the field of the present invention include U.S.Pat. Nos. 4,167,915, 4,268,538, 4,315,479 and 4,599,247.

SUMMARY OF THE INVENTION

The present invention is directed to an apparatus and method for growingsemiconductor quality oxide thermal layers on semiconductor wafers fastenough to be economically feasible as a single wafer process system. Allaspects of the apparatus and method of the present invention cooperatefor achieving adequate process conditions while providing reasonablewafer throughput. Process speed is insured by high pressure and hightemperature. For example, if the pressure is about 100 atmospheres(1,500 psi) and at a temperature of 900° C., approximately 2.66 minutesare required to grow a 5,000Å oxide layer in a steam environment. Thesystem can reach these operating conditions from ambient inapproximately 30 seconds and depressurization and cool down requireapproximately 60 to 90 seconds. Allowing 45 seconds for wafer handlingand overhead, a wafer throughput of approximately 12 wafers per hour isachievable with the present invention at the above operating conditions.

The apparatus of the present invention comprises a unique processingchamber adapted to be pressurized with an oxidant, such as high pressuresteam. The process chamber is contained in a pressure vessel adapted tobe pressurized with an inert gas, such as nitrogen, to a high pressure.

Another unique feature of the present invention is the use of a pressureequalizing scheme which keeps the pressure of the process chamber andthe pressure of the pressure vessel at substantially the same value. Thepressure equalization permits the use of thin walls for defining theprocess chamber and allows the apparatus of the present invention to behighly flexible, capable of a wide range of operating conditions, suchas from vacuum to high pressures, such as 100 atmospheres, and attemperatures ranging up to 900° C. and higher.

To obtain the required process rate and purity using the presentinvention, a semiconductor wafer is placed in the process chamber in thepressure vessel, following which the process chamber is pressurized withan oxidant, such as steam. Heaters outside the process chamber are usedto heat the interior of the chamber. The steam is ramped at a certainrate, such as 50 psi per second. Since the walls of the chamber must bethin to minimize thermal cool down, preventing breakage of the walls dueto fluid pressure differential requires a unique chamber-vesselseparation scheme which includes the pressure equalization scheme. Theprocess chamber is not physically sealed from the outer pressure vesselbut rather is isolated from it by a dynamic steam generation andcondensation arrangement which defines the pressure equalization scheme.

Steam is generated within a unique boiler at one end of the processchamber and within the pressure vessel. Steam flows through and out ofthe process chamber through an exhaust tube forming part of the pressureequalization scheme. Surrounding the steam exhaust tube is a watercooled condenser unit. This condenser unit condenses all the steam at alocation remotely from the pressure vessel in which the process chamberand steam generator are located.

During the ramping pressure cycle, water is injected into the boiler ata rate to generate steam faster than that required to pressurize theprocess chamber. If the process chamber were actually sealed, thepressurization rate would be greater than that of the pressure vessel.In reality, the system is open so that excess steam flows through thecondenser unit. As the pressure vessel is pressurized, the processchamber also pressurizes and the excess steam condenses in the condenserunit. The process chamber is filled with steam while the outer vessel isfilled with nitrogen. If more water is used than is required, then moresteam is condensed during operation, and if less water is used than isrequired, the nitrogen backfills to the steam exhaust, diluting theprocess steam. Once the process is complete, both the steam and nitrogenare exhausted through this condenser unit. No significant pressureacross the process chamber walls is generated during this cycle so thatno breakage is experienced.

The primary object of the present invention is to provide an improvedapparatus of method for processing semiconductor wafers, wherein theprocess is highly flexible and suitable for applying oxides to singlewafers at a high throughput while achieving optimum process conditions.

Other objects of this invention will become apparent as thisinvestigation progresses, reference being had to the accompanyingdrawing for an illustration of an embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the apparatus of the present invention forprocessing single semiconductor wafers at a high pressure andtemperature;

FIG. 2 is a top plan view of a body defining a process or reactionchamber for receiving a single semiconductor wafer to be processed,showing the steam generator attached to the body to form an integralunit therewith;

FIG. 2A is an end elevational view of the body of FIG. 2;

FIG. 2B is an enlarged, side elevational view of a pin for supportingthe wafer in the body of FIG. 2;

FIG. 3 is a schematic view of the apparatus, showing the body having thereaction chamber within a pressure vessel and closure means for closingthe pressure vessel and the body during the process;

FIG. 4 is an enlarged, fragmentary top plan view of the body, showingthe steam generator associated therewith;

FIG. 5 is a view similar to FIG. 4 but showing the steam generatorwithout the heaters and heat reflectors;

FIGS. 5A and 5B are vertical sectional views through the body of FIG. 2;

FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 5;

FIG. 7 is a side elevational view of the steam generator of FIGS. 4 and5;

FIG. 8 is an enlarged, fragmentary view of the body having the processchamber showing the relative positions of the wafer to be processed, thechamber itself and chill plates above and below the wafer;

FIG. 9 is a vertical section of the discharge tube for directing steamand nitrogen out of the process or reaction chamber and the pressurevessel;

FIG. 10 is a bottom plan view of the structure of FIG. 9; and

FIG. 11 is an enlarged, fragmentary, sectional view of an actuator formanipulating the closures for the pressure vessel and the body havingthe reaction chamber.

DETAILED DESCRIPTION OF THE DRAWINGS

Apparatus for processing a semiconductor wafer in accordance with thepresent invention is broadly denoted by the numeral 10 and includes apressure vessel 12 (FIGS. 1 and 3) for containing a hollow body 14having a reaction or process chamber 16 therein for processing asemiconductor wafer 18. The apparatus operates to grow an oxide layer ofsemiconductor quality on a wafer in process chamber 16, the growth beingfast enough to be economically feasible as a single wafer processsystem. All elements of apparatus 10 have been designed for achievingboth adequate processing conditions and reasonable throughput.

Pressure vessel 12 is shown schematically in detail in FIG. 3 andincludes a box-like housing which is coupled to a source 13 (FIG. 1) ofan inert gas, such as nitrogen, the housing having a lower part 20 andan upper part 22, the upper part 22 forming a lid for the open top oflower part 20. The dimensions of the parts 20 and 22 of pressure vessel12 are chosen so that the interior space 24 of the pressure vessel canwithstand fluid pressures of over 100 atmospheres (above 1,500 psi).Typically, the lower part 20 of pressure vessel is formed of stainlesssteel and the upper part 22 is formed of aluminum. However, anycombination of materials can be used.

The upper part 20 is pivotally mounted on the lower part 22 for rotationabout a generally vertical axis (not shown) so that the upper part 22can easily pivot into and out of a position closing the open top oflower part 20. Thus, access to space 24 can be had when the open top oflower part 20 is open.

The pressure vessel 12 has a wafer access opening 26 (FIG. 3) in theside wall of the lower part 20. The access opening 26 is adjacent to awafer transfer mechanism 28 of conventional design externally ofpressure vessel 12. Transfer mechanism 28 has a pivotal plate 29 adaptedto insert a wafer into pressure vessel 12 and into body 14 havingreaction chamber 16. Mechanism 28 is also adapted to remove a wafer 18from reaction chamber 16 and from pressure vessel 12 after the wafer hasbeen processed in the reaction chamber.

The wafer is moved into and out of the reaction chamber when a closuremechanism 30 is in the dashed line position of FIG. 3. Mechanism 30 ismovable under the influence of a power device 32 (FIG. 11) to move apair of closure members 34 and 36 (FIG. 3) into closing relationship toaccess opening 26 of pressure vessel 12 and of access opening 38 (FIGS.2A and 3) at the entrance end of body 14 having process chamber 16therein. Power device 32 will be described hereinafter in more detail.

Body 14 is generally rectangular in shape as shown in FIG. 2. It iscomprised of thin walls (2 mm thick), including upper and lower walls 40and 42, a pair of side walls 44 and 46 and a pair of end walls 48 and50. The walls of body 14 are formed of a high purity material, such asquartz, an end wall has opening 38 therein as shown in FIG. 3. Wall 48further includes an outer peripheral flange which mates with a quartzelement 52 (FIG. 3) carried by closure member 36. When the closuremember 36 is in the full line position of FIG. 3, quartz element 52closes opening 38, thereby blocking access to the reaction chamber 16 ofbody 14. Conversely, when closure member 36 is in the dashed lineposition of FIG. 3, element 52 will be out of closing relationship toopening 38 and a wafer 18 can be moved into or out of reaction chamber16 by the action of mechanism 28.

Body 14 having reaction chamber 16 therein can be mounted in anysuitable manner within the lower part 20 of pressure vessel 12. Forinstance, quartz sleeves 54 (FIG. 5A) can be integral with body 14 anumber of spaced locations, respectively, and each sleeve can receive arod (not shown) coupled to the inner surface of lower part 20 ofpressure vessel 12 in any suitable manner so that body 14 will beeffectively supported from beneath so that the entrance opening 38 ishorizontally and vertically aligned with the access opening 26 in lowerpart 20 of pressure vessel 12.

Lower wall 42 of body 14 is provided with 3 spaced pegs or pins 56 onits upper surface as shown in FIGS. 2 and 2B for supporting a wafer 18in a horizontal position within process chamber 16. The cross section ofeach pin 56 is shown in FIG. 2B in which a horizontal surface 58 isadjacent to an inclined surface 60, the inclined surface being providedto allow the wafer to be centered on horizontal surface 58 in the eventthat mechanism 28 does not properly seat the wafer on surface 58.Mechanism 28 typically will include plate 29 which lifts a wafer 18 outof a cassette of conventional construction and moves the wafer into andthrough opening 26 and opening 38 and onto pins 56, whereupon the platewill be lowered slightly and then retracted out of openings 26 and 38,leaving the wafer on surfaces 58 of pins 56 for processing.

A steam generator 62 of high purity material, such as quartz, is coupledwith body 14 at side wall 50 of the latter as shown in FIG. 2. Steamgenerator 62 includes a first tube 64 having an inlet end 66 forreceiving deionized water from a source 67 (FIG. 1) of such water. Tube64 is connected to a U-shaped end portion 68 which in turn is coupled toa second tube 70 within a larger tube 72. Tubes 70 and 72 are closed atadjacent ends 74 and 75 thereof and tube 70 has holes 76 (FIG. 7) at theupper extremity thereof, placing tube 70 in fluid communication withtube 72. Side tubes 77 coupled to tube 72 extend to end wall 50 (FIG. 2)of body 14, thereby placing tube 72 in fluid communication with processchamber 16.

Tube 64 is provided with a series of spaced baffles 78 extending intothe tube from the inner periphery thereof. Each baffle 78 has the shapeas shown in FIG. 6 and the baffles 78 are staggered so as to form aserpentine path for deionized water and vapor for flow through the tube64 to tube 70.

Holes 76 are in tube 70 to allow vapor to rise in tube 70 and enter tube72, but the holes are placed so that water cannot enter tube 72 fromtube 70, thereby assuring that only vapor will pass upwardly and intotube 72 and thereby into reaction chamber 16. If water were to enterreaction chamber 16, it would impair the action of the process inreaction chamber 16. Also, tube 64 is inclined as shown in FIG. 7relative to horizontal attitude of tube 72 so that water will tend toflow downhill in the event that water tends to flow through tube 64.

A pair of cylindrical, electrical resistance heaters 80 and 82 surroundtwo parts of tube 64 as shown in FIG. 4. Heaters 80 and 82 are of a highpurity material, such as graphite, and the heaters are coupled to somesuitable source of electrical power so that heat energy will be radiatedinto and conducted through tube 64 for heating the deionized water to avapor flowing therethrough.

Each of heaters 80 and 82 has a series of spaced, quartz shells 84 (FIG.4) concentric to and surrounding tube 64. Shells 84 are coated on theirouter surfaces with aluminum oxide to reduce heat losses. The shellsthus serve to reflect the heat energy back into tube 64 instead ofoutwardly into the ambient atmosphere. Thus, shells 84 render theheaters 80 and 82 more efficient.

A cylindrical heater 88 (FIG. 4) surrounds tube 70 for heating furtherthe water vapor therein to a high temperature, such as 900° C. Heater 88extends throughout a major portion of the length of tube 72 and isprovided with a plurality of spaced, coated, quartz shells 90concentrically surrounding tube 72 for the same purpose as shells 84.

Electrical resistance heaters 92 and 94 are mounted on body 14 as shownin FIG. 8, heater 92 being above and in proximity to top wall 40 andheater 94 being below and in proximity to bottom wall 42 of body 14.Heaters 92 and 94 are flat, planar heaters and heat the wafer 18 andsteam within process chamber 16 of body 14.

Chilling plates 96 and 98 are mounted in some suitable manner withinpressure vessel 12. Chill plates 96 and 98 have coolant passages 100 and102 therethrough to allow coolant to pass therethrough for chilling thewafer before, during and after the processing of the wafer. A suitablesource 103 (FIG. 1) of coolant is provided in apparatus 10 to supplycoolant to chill plates 96 and 98.

A discharge tube 104 (FIG. 2A, 5A and 5B) is coupled to body 14 andextends outwardly and downwardly therefrom. Tube 104 is of quartz andextends partially through condenser unit 105 (FIG. 9) which includes aflange 107a on open end 106 adapted to be secured to and extenddownwardly from pressure vessel 12. Condenser 105 has a central passage107 therethrough surrounded by wall 109 having a coolant passage 110therein. Coolant is supplied from a coolant source to a pair of tubes112 and 114 (FIG. 10). Central passage 107 is coupled by a tube 116 to avalve 115 (FIG. 1) for venting the tube 104 and passage 107 to areservoir 111 (FIG. 1).

Tube 104 as shown in FIG. 2 has a thermocouple 118 near its lower endwhich is used to sense the temperature of the steam exiting or tendingto exit through the tube 104 from chamber 16. In this way, the pressureof the nitrogen in pressure vessel 12 and the pressure of the steam inreaction chamber 16 can be equilibrated at all times so that there willbe a balance of the two pressures so that the two pressures will besubstantially equal at all times. If the pressure of the steam is toohigh, the steam will tend to flow out of tube 104 and be condensed onwall 109. If the pressure of the nitrogen is too great, it will tend toflow into tube 104 and into process chamber 16 which is clearlyundesirable. By monitoring these two pressures by sensing thetemperature of the steam exhaust, equalizing the pressures can beachieved.

In reality, the system is open. As the outer vessel 12 is pressurized,the process chamber 16 is also pressurized and the excess steam iscondensed on the condenser wall. The process chamber 16 is entirelyfilled with steam while the outer pressure vessel 12 is filled entirelywith nitrogen. If more water is used than is required, then more steamis condensed during operation and if less water is used than isrequired, nitrogen flow through the steam exhaust tube 104 diluting thesteam.

Power device 32 (FIG. 11) is coupled to closure members 34 and 36 by wayof a rod 120 which extends through a hole 122 in the bottom 124 ofpressure vessel 12 as shown in FIGS. 3 and 11. Rod 120 is coupled toclosure members 34 and 36 to raise the closure members from the dashedline positions of FIG. 3 to the full line positions of FIG. 3 when rod120 moves upwardly relative to bottom wall 124 of pressure vessel 12.

Closure members 34 and 36 move upwardly until at least one of themembers, such as member 34, strikes a stop 128 (FIG. 3), following whichthe vertical movement of closure members 34 and 36 stops while lateralmovement takes over due to a pivotal linkage (not shown), moving theclosure members 34 and 36 into closing relationship to access openings26 and 38, respectively. The closure members are spring-biased towardeach other so that when the pressure of the rod 120 is relaxed, closuremembers 34 and 36 move inwardly toward each other and open accessopenings 26 and 38, respectively.

Rod 120 is mounted within a tube 130 coupled by a flange 132 to thebottom surface of bottom wall 124 of pressure vessel 12 (FIG. 11). Rod120 carries a number of stacked magnets 133 thereon which aremagnetically coupled to other permanent magnets 134 surrounding tube130. Magnets 134 are coupled to a frame 136 having a lower plate 138coupled to piston rod 140 of an air cylinder 142. Cylinder 142 iscoupled to the lower end of tube 141, the latter being stationarilymounted on a rigid support 144, such as a support coupled to the bottomwall 124 of pressure vessel 12.

As cylinder 142 is actuated, piston rod 140 is elevated to raise magnets134. As magnets 134 move upwardly, magnets 132 also move upwardlybecause of the magnetic coupling between the magnets. This causes rod120 to move upwardly to cause the closure members 34 and 36 to raise tothe full line positions of FIG. 3 or until closure member 34 engagesstop 128. Then, the closure members 34 and 36 move laterally and intoclosing relationship with respective access openings 26 and 38. Asuitable pivotal linkage causes the lateral movement of closure members34 and 36 as is well known.

As soon as piston rod 140 is allowed to lower, rod 120 moves downwardly,causing closure members 34 and 36 to move toward each other and thendownwardly into the dashed line positions of FIG. 3. The power device ofFIG. 11 can thus be implemented without the need for elaborate seals.

An end-of-process window 140 is provided in pressure vessel 12 as shownin FIG. 3. Window 140 is part of upper part 22 of the pressure vessel 12and includes a window insert 142 which can be circular and adapted to beinserted into an opening 144 in the top portion of vessel part 22.Insert 142 has a hole 146 formed therein and covered with a transparentglass pane 148 to form a window aligned with a hole 150 in the nextadjacent chill plate 96. A laser beam 152 can be coupled to a lasersource 154 carried by window 140 for directing the laser beam onto wafer18 in process chamber 16 to determine the characteristics of the oxideon the wafer 18 by interference techniques. Insert 142 has an annularflange in sealing relationship to the outer surface of top part 22 ofvessel 12 to close the interior of pressure vessel 12 from theatmosphere.

In operation, nitrogen is supplied from source 13 (FIG. 1) to theinterior of pressure vessel 12 and steam is supplied to the interior ofbody 14 having reaction chamber 16 therein. These gases are directedinto respective chambers after a wafer 18 has been placed withinreaction chamber 16.

Process speed is ensured by high pressure; for example, 100 atmospheres(1,500 psi) and high temperature; for example, 900° C. At theseoperating conditions, the time to grow an oxide layer of 500Å thick in asteam environment is about 2.667 minutes. A system of the presentinvention can reach these conditions from ambient in approximately 30seconds. Depressurization and cool down requires 60 to 90 seconds withthe possibility of 30 seconds. Allowing 45 seconds for wafer handlingand overhead, a throughput of approximately 12 wafers per hour isachievable with apparatus 10.

To obtain the required process rate and purity, a wafer 18 is placed inprocess reaction chamber 16 and filled with steam. All heaters areoutside chamber 16 which is contained within pressure vessel 12 havingnitrogen therein. This arrangement of the quartz body 14 filled withsteam inside a pressure vessel 12 filled with nitrogen is ramped atnearly 50 psi per second to meet the operational requirements. Since thequartz body 14 must be thin, such as 2 mm thick (to minimize thermalcool down), preventing breakage requires a unique chamber separationscheme.

The inner chamber 16 is not physically sealed from the outer pressurevessel but rather isolated by condensation unit 105 (FIG. 9). Steam isgenerated by a steam generator 62 at one end of body 12, and steam flowsthrough chamber 16 and out through tube 104. Surrounding tube 104 iscondenser unit 105 to form a trap which condenses all the steam remotelyfrom the pressure vessel 12 in which the chamber 16 and steam generator62 are located.

During the ramping pressure cycle, water is injected into the steamgenerator at a rate that generates steam faster than that required topressurize the process chamber 16. If chamber 16 were actually sealed,the pressurization rate would be greater than that of the surroundingpressure vessel 12. The system is open so that exit steam flows throughcondenser unit 105 as the outer vessel 12 pressurizes.

Once the process is complete, both the steam and nitrogen are exhaustedto the atmosphere through the steam condenser unit 105. No significantpressure differential across the quartz walls of body 14 is generatedduring the cycle so that no breakage is experienced.

The steam generator 62 has a unique baffle design in which the baffles78 are also made of quartz as is the tube 64 which carries the baffles(FIG. 5 and 6). The baffles reduce the blowing water as the water isbeing turned into steam. The entire steam generator is of high puritymaterial, such as quartz to prevent contamination of the interior ofprocess chamber 16 and thereby avoid contamination of a wafer 18 in theprocess chamber. The manifold provided by tubes 70 and 72 of steamgenerator 62 cooperate with the holes 76 in tube 70 to prevent all waterdrops from entering process chamber 16.

The boiler heaters 80, 82 and 88 (FIG. 4) are of high purity material,such as graphite, and provide for minimal metal contamination of thequartz material of the steam generator 62. The segmented heaters 80 and82 and the single manifold heater 88 distribute heat energy as neededfor the generation of steam in steam generator 62. There is no need toinsulate the heaters, thereby eliminating a principal source of wafercontamination.

The process chamber heaters 92 and 94 are unique in heating chamber 16in that the entire chambers area is heated at a specific operatingtemperature. There is rapid heat up due to high power heaters 92 and 94.There is also rapid cool down due to the close proximity of the chillplates 96 and 98 and the small thermal mass of body 14. Heaters 92 and94 are of high purity graphite so as to provide for no metalliccontamination of the interior of pressure vessel 12 or body 14. Thereare no fibrous insulators so as to provide for less contamination andreduced particles. The design of body 14 is suitable for broad pressureratings including a vacuum through 100 atmospheres.

I claim:
 1. Apparatus for processing a semiconductor wafer comprising:apressure vessel; a hollow body within the pressure vessel and having aprocess chamber, said pressure vessel and said body having respectiveopenings for receiving a semiconductor wafer as the wafer moves from alocation exteriorly of the pressure vessel to a location within theprocess chamber; means coupled with the pressure vessel and said bodyfor closing the openings; means coupled with the body for directing anoxidant at high pressure into the process chamber, said body having afirst tube for discharging oxidant therefrom, there being a second tubesurrounding the first tube for discharging an inert gas from thepressure vessel; means for directing an inert gas under pressure intothe pressure vessel; means for heating the oxidant in the processchamber; means for cooling the body after the wafer in the processchamber has been processed; and means coupled with the pressure vesseland the body for equilibrating pressures of the inert gas and theoxidant and for isolating the inert gas from the oxidant, saidequilibrating means including means near the outer end of the first tubefor sensing the temperature of the oxidant at said discharge means. 2.Apparatus as set forth in claim 1, wherein said body is formed ofquartz.
 3. Apparatus as set forth in claim 1, wherein said means fordirecting an oxidant into the process chamber includes a steam generatorhaving a fluid inlet, and a source of deionized water coupled to theinlet of the steam generator.
 4. Apparatus as set forth in claim 3,wherein the steam generator includes a tube having a fluid inlet and aseries of spaced baffles for forming a serpentine path for fluid throughthe tube.
 5. Apparatus as set forth in claim 4, wherein said tube andthe baffles are formed of quartz.
 6. Apparatus as set forth in claim 4,wherein is included a heater surrounding the tube for heating the fluidflowing through the tube.
 7. Apparatus as set forth in claim 1, whereinsaid oxidant heating means includes a heater within the pressure vesseland in proximity to and outside said body for heating the interior ofthe process chamber.
 8. Apparatus as set forth in claim 7, wherein saidheater means includes a pair of planar heaters above and below the body.9. Apparatus as set forth in claim 8, wherein said body has a flat upperwall and a flat lower wall, said planar heater being adjacent torespective upper and lower walls.
 10. Apparatus as set forth in claim 1,wherein said cooling means includes a chill plate adjacent to the body.11. Apparatus as set forth in claim 8, wherein said body includes anupper wall and a lower wall, said cooling means includes an upper chillplate and a lower chill plate near respective upper and lower walls, andmeans coupling the chill plates to a source of coolant.
 12. Apparatus asset forth in claim 1, wherein said equilibrating and isolating meansincludes a condenser unit coupled in fluid communication with thepressure vessel and said body.
 13. Apparatus as set forth in claim 1,wherein said closure means includes a pair of closure members within thepressure vessel and movable into closing relationship to the openings ofthe pressure vessel and the body, respectively, and means for moving theclosure members into and out of the operative positions thereof. 14.Apparatus as set forth in claim 1, wherein is included a steam generatorin the pressure vessel is operable to pressurize the process chamber toa pressure of at least 100 atmospheres, and means for supplying theinert gas to the interior of the pressure vessel at a pressure of atleast 100 atmospheres.
 15. Apparatus as set forth in claim 1, wherein isincluded means for heating the steam in the reaction chamber to atemperature in the range of 800° C. to 1000° C.
 16. Apparatus forprocessing a semiconductor wafer comprising:a pressure vessel; a hollowbody within the pressure vessel and having a process chamber, saidpressure vessel and said body having respective openings for receiving asemiconductor wafer as the wafer moves from a location exteriorly of thepressure vessel to a location within the process chamber; means coupledwith the pressure vessel for closing the openings; a steam generatorhaving a fluid inlet and being coupled with the body for directing anoxidant at high pressure into the process chamber, said steam generatorhaving a first tube provided with said fluid inlet and a series ofspaced baffles for forming a serpentine path through the first tube,said steam generator including a second tube coupled to the first tubeand a third tube surrounding the second tube, there being holes in thesecond tube for placing the second and third tubes in fluidcommunication with each other, there being a heater surrounding thethird tube; a source of deionized water coupled to said inlet; means fordirecting an inert gas under pressure into the pressure vessel; meansfor heating the oxidant in the process chamber; means for cooling thebody after the wafer in the process chamber has been processed; andmeans coupled with the pressure vessel and the body for equilibratingpressures of the inert gas and the oxidant and for isolating the inertgas from the oxidant.
 17. Apparatus as set forth in claim 16, whereinthe holes are in the upper extremity of the second tube.
 18. Apparatusas set forth in claim 16, wherein the third tube is provided with meansfor placing the third tube in fluid communication with the processchamber.
 19. Apparatus as set forth in claim 16, wherein the second andthird tubes are formed of quartz.
 20. Apparatus for processing asemiconductor wafer comprising:a pressure vessel; a hollow body withinthe pressure vessel and having a process chamber, said pressure vesseland said body having respective openings for receiving a semiconductorwafer as the wafer moves from a location exteriorly of the pressurevessel to a location within the process chamber; means coupled with thepressure vessel for closing the openings; means coupled with the bodyfor directing an oxidant at high pressure into the process chamber;means for directing an inert gas under pressure into the pressurevessel; means for heating the oxidant in the process chamber; means forcooling the body after the wafer in the process chamber has beenprocessed; and means for equilibrating pressures of the inert gas andthe oxidant and for isolating the inert gas from the oxidant, saidequilibrating and isolating means including a condenser unit coupled influid communication with the pressure vessel and said body, saidcondenser unit including a first tube coupled with and in fluidcommunication with the pressure vessel, means for releasably opening andclosing the interior of the first tube, there being a second tube withinthe first tube, said second tube having an outer open end, the firsttube being in fluid communication with the second tube, whereby fluidpressures in the pressure vessel and the reaction chamber can bebalanced and equalized by preventing the oxidant to exit from the secondtube and by preventing the inert gas in the pressure vessel fromentering the second tube.
 21. Apparatus for processing a semiconductorwafer comprising:a pressure vessel; a hollow body within the pressurevessel and having a process chamber, said pressure vessel and said bodyhaving respective openings for receiving a semiconductor wafer as thewafer moves from a location exteriorly of the pressure vessel to alocation within the process chamber; means coupled with the pressurevessel for closing the openings, said closing means including a pair ofclosure members within the pressure vessel and movable into closingrelationship to the openings of the pressure vessel and the body,respectively, and means for moving the closure members into and out ofthe operative positions thereof, said means for moving the closuremembers including an elongated rod shiftably extending through thepressure vessel, said rod having a first magnet thereon and beingdisposed within a closed tube, a second magnet externally of the tubeand movable longitudinally thereof, a fluid actuated power device formoving the second magnet along the tube to move the first magnet andthereby the rod relative to the pressure vessel; means coupled with thebody for directing an oxidant at high pressure into the process chamber;means for directing an inert gas under pressure into in the pressurevessel; means for heating the oxidant in the process chamber; means forcooling the body after the wafer in the process chamber has beenprocessed; and means coupled with the pressure vessel and the body forequilibrating pressures of the inert gas and the oxidant and forisolating the inert gas from the oxidant.